Location: Children's Nutrition Research CenterTitle: Nuclear magnetic resonance metabolomics of iron deficiency in soybean leaves Author
|Lima, Marta - Universidade Catolica Portuguesa|
|Diaz, Silva - University Of Aveiro (UA)|
|Lamego, Ines - University Of Aveiro (UA)|
|Vasconcelos, Marta - Universidade Catolica Portuguesa|
|Gil, Ana - University Of Aveiro (UA)|
Submitted to: Journal of Proteome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2014
Publication Date: 6/6/2014
Citation: Lima, M.R., Diaz, S.O., Lamego, I., Grusak, M.A., Vasconcelos, M.W., Gil, A.M. 2014. Nuclear magnetic resonance metabolomics of iron deficiency in soybean leaves. Journal of Proteome Research. 13(6):3075-3087.
Interpretive Summary: Soybean is one of the most economically important crops worldwide, being used as a food crop for humans or as forage for animals. To produce healthy plants, soils must be rich in several minerals. Unfortunately, there are some soil situations where certain minerals, such as iron, are in low abundance. This situation results in lower yields and soybean seeds or forage of reduced nutritional quality. We are interested in learning how to make soybean plants grow better when challenged with limited iron. To do this, we grew plants with or without iron and harvested leaves in order to study what types of chemical compounds the plants make when they are healthy, compared to when they are iron starved. We learned that the concentrations of some compounds changed as plants became iron-starved, and some chemical changes could be seen even before the plants showed visible signs of iron deficiency (yellowed leaves). These results will help us develop ways to monitor plants and correct deficiencies even before severe leaf symptoms occur.
Technical Abstract: Iron (Fe) deficiency is an important agricultural concern leading to lower yields and crop quality. A better understanding of the condition, at the metabolome level, could contribute to the design of strategies to ameliorate Fe deficiency problems. Fe-sufficient and Fe-deficient soybean leaf extracts and whole leaves were analyzed by liquid 1H nuclear magnetic resonance (NMR) and high resolution magic angle spinning (HRMAS) NMR spectroscopy, respectively. Overall, 30 compounds were measurable and identifiable (comprising amino and organic acids, fatty acids, carbohydrates, alcohols, polyphenols and others), along with 22 additional spin systems (still unassigned). Metabolite differences between treatment conditions could be evaluated for different compound families simultaneously. Statistically relevant metabolite changes upon Fe deficiency included higher levels of alanine, asparagine/aspartate, threonine, valine, GABA, acetate, choline, ethanolamine, hypoxanthine, trigonelline and polyphenols, and lower levels of citrate, malate, ethanol, methanol, chlorogenate and 3-methyl-2-oxovalerate. The data indicate that the main metabolic impacts of Fe deficiency in soybean include enhanced tricarboxylic acid cycle activity, enhanced activation of oxidative stress protection mechanisms, and enhanced amino acid accumulation. Metabolites showing accumulation differences in Fe starved, but visually asymptomatic leaves, could serve as biomarkers for early detection of Fe-deficiency stress.